揭示在选择性碳酸氧化过程中在低价值Cu位点上生成的 OH 位物
Yang Cao1, Qiaozhi Zhang2, Iris K M Yu2
1Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong 999077, China.
概括
这项研究揭示了铜催化剂的新催化氧化途径,其中表面基 (*OH) 选择性氧化葡萄糖到葡萄糖酸. 这种机制与Mars-van Krevelen模型不同,为生物质转化提供了增强的选择性.
科学领域:
- 催化剂是一种催化剂.
- 表面化学 表面化学
- 绿色化学 绿色化学
背景情况:
- 火星-范克雷文机制是金属氧化物催化氧化的主要模型.
- 忽略了一种涉及表面基物种的替代氧化途径.
研究的目的:
- 对铜催化剂的替代氧化机制进行研究.
- 了解表面基在葡萄糖氧化中的作用.
- 阐明生物质分子选择性氧化反应途径.
主要方法:
- 用X射线光谱分析铜催化剂的价值状态.
- 使用D2O的动态同位素效应 (KIE) 研究.
- 在现场拉曼光谱.
- 密度函数理论 (DFT) 的计算.
主要成果:
- 低价值Cu位点 (Cu0/Cu+) 激活分子氧,形成局部的表面基 (*OH).
- 这些OH*物种在C1位置选择性氧化葡萄糖,产生高达91%的选择性葡萄糖酸.
- 氧化机制涉及限制速度的*OH添加到碳基,而不是C1-H激活.
结论:
- 已经确定了一种涉及表面OH物种的新型催化氧化机制.
- 这一途径为葡萄糖氧化提供了优越的选择性,与大量自由基相比.
- 控制表面 *OH覆盖和活性可以使碳化合物在水性环境中使用非贵金属催化剂实现高性能氧化.
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